This house-sized space rock reached the closest point of its flyby this morning at about 6.40am, passing within 27,200 miles of the surface of Antarctica before beginning its journey past the moon and back out into space.

“That’s what I’ve been using as kind of an analogy to what we’re doing here.”
Observatories that are part of the International Asteroid Warning Network have been zooming in on TC4 for weeks to test communication and coordination.

Until now, researchers relied on “tabletop” tests, simulations with no actual asteroids involved. The exercise will continue for another week, as observatories keep tracking the asteroid as it zooms back off into space.

Astronomers first spotted TC4 in 2012. It is believed to be between 14 and 30 metres wide.

Scientists are interested in the asteroid because there is some uncertainty about its path.

They used major telescopes in Hawaii, Arizona and other places around the world to watch the space rock zoom past and will follow the space rock at it travels back out into space.

Backyard astronomers have little chance of seeing the asteroid, given its speed and faintness. It won’t be visible with the naked eye anywhere in the world, let alone Britain where it’s now daylight.

The communication lines for the test have extended all the way to the Federal Emergency Management Agency and even the White House, according to Kelley, who’s leading the effort for NASA’s Planetary Defense Coordination Office.

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In 2013, a meteor which was about the same size as TC4 exploded in the atmosphere over the city of Chelyabinsk in central Russia with the kinetic energy of about 30 Hiroshima atom bombs.
The resulting shockwave blew out the windows of nearly 5,000 buildings and injured more than 1,200 people.

Local footage captured the fireball streaking across the sky, and some witnesses claim they felt intense heat.

A 40-metre space rock that was slightly bigger than TC4 caused the largest Earth impact in recent history when it exploded over Tunguska, Siberia, in 1908.

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